Comments on CD's criticism of the harsh tone of Generelle Morphologie. Thinks he may have harmed himself but not the cause. Believes a radical reform of the science necessary, and since most scientists take a prejudiced view of the matter, a vigorous attack is essential.

Translation

Jena

12. May 1867

My dear, most admired friend!

Having only been back from my travels a few days, I found your
kind letter of 12. April along with the new edition of your
epoch-making work. For both I express my most heartfelt
thanks. Unfortunately, I can see from your letter that you have not
received a long letter that I write to you several months ago, and
that contained an enclosure for our friend Huxley. Given the great
disorder that dominates the sloppy Spanish post on the Canary
Islands, I certainly cannot say I am surprised. On the other hand, I did receive
your first letter, sent to Madeira, although 2 months later, on
Lanzarote.

Now, let me first of all dear friend, repeat my most heartfelt
thanks for the exceedingly friendly reception that I enjoyed in your
dear home. That day, which I was privileged to spend with you and to
which I had looked forward for so long will always be unforgettable to
me.

I cannot tell you how exceptionally happy you made me by allowing
me to visit you, and what immense satisfaction I got from becoming
personally acquainted with the naturalist who, as reformer of the
theory of descent and discoverer of natural selection, has had a
greater influence on the direction of my studies and my life's work
than anyone else. Once more I send you and your dear family my most
heartfelt and sincere thanks.

I hope your health is improving now, and you can again devote
your great knowledge and your thoughtful examination of nature to the
progress of our sciences. When on my travels I got to know the
wonderful climate of Madeira and the Canary Islands, I often wished
that you were with us in order permanently to strengthen your weakened
health. I myself returned to my old strength there and recovered
completely from the strains inflicted on me by work in the last few
years.

It gives me very great satisfaction that you liked my general
morphology overall, and your praise is the highest reward for my
efforts. I am especially pleased, however, about your frank, critical
remarks on the shortcomings of the work, since this shows that you
consider me worthy of the most honest friendship. Your reproach about
the excessive sharpness of my critical attacks and the bitterness of
my polemics is certainly justified. My best friends here, especially
Prof. Gegenbaur, have also reproached me strongly for this. In my
defence, I can only say that when I wrote the book in dismal solitude
last summer and winter, I was in an extremely bitter mood and
suffering from
irritation of the nerves. I also felt too angry about your opponents' impertinent and
stupid attacks to let them get away with it unpunished. In any case,
my attitude has been very damaging to me personally and I have been
attacked no less vehemently from many sides. But I am completely
indifferent to this, since my personal reputation and the esteem of
contemporaries matter little to me. Long may my many enemies attack
my work strongly; it just contributes to its spread. Whether they
rebuke and malign me is unimportant to me.

But I should be very sad if my too vehement attacks were to damage
the good cause for which we both fight. My friend Gegenbaur, whom I
love like a brother, is of this opinion and he is very indignant about
my literary excesses. You too, most honoured sir, seem to share
this fear.

I admit that in this respect I am not quite of your opinion and
that I find you unduly worried. Your apprehension would be justified
if one could expect an independent, impartial attitude and a fair judgement of both sides from the majority of today's
naturalists. But unfortunately this is emphatically not the case. Rather,
we see that the large majority do not make an independent judgement,
do not have a distinct and clear conviction of the claims of
truth. And so, I think, it is necessary to speak the truth loud and
clear and not spare the opponents' weaknesses.

It seems to me, we are now dealing with a radical reform of the
whole of science, a reform that you, most honoured Sir, have initiated with your
grounding of the theory of descent in mechanical causation. Such a
reformation, which has everywhere to fight immense obstacles and prejudices, can
never be won with soft words and benevolent persuasion. Rather,
energetic attacks and merciless blows are everywhere necessary in
demolishing the old edifice of persistent errors. As with all
struggles, here too, the bold attacker has great advantages and thus I
thought it wiser to attack mercilessly myself than to be assaulted by
my malevolent opponents.

When I see how unfairly and wrongly your great work is judged in
various ways, how even you personally are maligned, then all my
respect for the great audience of naturalists vanishes. Your
extraordinary humility is seen as weakness and your admirable
self-criticism is interpreted as lack of firm conviction. Of course
with good, understanding and thinking men you have only gained by this. But unfortunately these are in the minority. If instead I have
approached the issue much more trenchantly and polemically, then I really
can hardly believe I have damaged the cause in the long term. In any
case, I hope I have contributed something to the diffusion of your
great ideas and your pioneering reform, and to have formulated firmly
some important and relevant questions and brought them into the public domain, where
open discussion can only promote the topic and reveal the truth. Like
you, esteemed sir, I trust, first and foremost, the receptive and
unprejudiced nature of younger scientists, and I have no doubt that
we will surely encounter much greater and keener interest among the
now flourishing generation. Already in the few days since I have been back,
I have noticed this again. I immediately started giving my lectures on
the theory of descent once more, and I feel with lively enjoyment the
warm support, even more spririted than before, that the < >
academic youth gives our cause.

By the way, in future I shall heed your benevolent, paternal
advice, for which I sincerely thank you, and I shall rein in my all
too keen and passionate pen. You would grant me the most honest
friendship, dear Sir, if in future you continue to draw my attention so
openly to the mistakes in my work.

I will soon send you a printed report on my travels. I was only
briefly in Madeira, just 14 days on Tenerife (where I climbed the
Pic), but 3 months on Lanzarote, where I primarily studied the
development of the glorious Siphonophores and Atlantic Radiolaria. In
March I spent 14 days in Morocco and 14 days in Gibraltar. In the
first half of April I travelled through Seville, Cordova, Granada
(!) Madrid; the second half I spent studying the remarkable Exposition
universelle in Paris. My health was splendid all the time and I am
very satisfied with the result of the journey.

I may, perhaps, come to England some time this year (in the autumn),
and I would be very pleased if I could see you again in better
health. In the meantime, dear Sir, please accept again my warmest
thanks for your sincere friendship, and the request that it may continue in future.

Haeckel had spent from November 1866 to March 1867 travelling and doing
research on Tenerife and Lanzarote; he also visited Morocco, Portugal, and
the Spanish mainland (see Haeckel 1867). Haeckel also refers to the letter
from CD of 12 April [1867], and the fourth edition of Origin.
Haeckel's name appears on the presentation list for this book (see
Correspondence vol. 14, Appendix IV).

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f3 5533.f3

Neither the letter to CD nor the letter to Thomas Henry Huxley has been
found. For transcripts of the extant correspondence between Haeckel and
Huxley, see Uschmann and Jahn 1959--60. Haeckel wrote to Huxley on
12 May 1867 (Uschmann and Jahn 1959--60, pp. 11--12; the letter is at the
Imperial College of Science and Technology), mentioning the enclosure to the
letter to CD that went astray. The Canary Islands, which include Tenerife
and Lanzarote, are governed by Spain (EB).

+

f4 5533.f4

Haeckel presumably refers to the letter from CD of 8 January 1867.

+

f5 5533.f5

Haeckel had visited CD at Down House in October 1866 (see
Correspondence vol. 14). On their meeting, see also A. Desmond
and Moore 1991, pp. 539--40.

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f6 5533.f6

See letter to Ernst Haeckel, 12 April [1867] and n. 6.

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f7 5533.f7

Carl Gegenbaur.

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f8 5533.f8

Haeckel gave lectures on CD's theory of descent both to students at Jena
University and to the general public, but these seem to have been given in
the winter (see Uschmann 1959, p. 45; see also Correspondence
vol. 14, letter from Ernst Haeckel, 11 January 1866 and n. 14). His lectures
given in the winter of 1867 to 1868 were published as Haeckel 1868 (see
Uschmann 1959, p. 45), which was translated as Haeckel 1876.

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f9 5533.f9

Haeckel sent a preliminary report on his travels to CD with his letter of
28 June 1867; this report has not been found in the Darwin Archive--CUL. A
report was also published on 12 September 1867 in the Jenaische
Zeitschrift für Medicin und Naturwissenschaft (Haeckel 1867).

+

f10 5533.f10

The highest point of the Pico de Teide on Tenerife is 3770 m (Times
atlas). For Haeckel's account of the climb, see Uschmann 1984,
pp. 92--6.

+

f11 5533.f11

Haeckel published his research on siphonophores in 1869 (Haeckel 1869).